In a small business aircraft, a DC starter/generator is utilized in a starting mode to convert DC power supplied by a battery into motive power for starting main engines. Thereafter, the starter/generator is operable in a generating mode to provide up to a maximum current rating at a particular voltage, such as 200-400 amps at 28 volts DC. Engine start power requirements have grown over time, resulting in increasing unreliability of the DC starter/generator. In addition, loads have also increased, leading to the need to add a separate wound-field AC generator to the engine to supply a portion of the loads. This, in turn, results in the need for two gear box pads to drive the two types of generators. Further, the DC starter/generator is a source of high life cycle costs due to maintenance of the brushes thereof.
The addition of a further machine to the engine gear box to supply power to loads results in reduced reliability of the overall system.